ProcDef
  Ident "test"
  Empty
  Empty
  FormalParams
    Ident "bool"
    IdentDefs
      Ident "a"
      Ident "bool"
      Empty
    IdentDefs
      Ident "b"
      Ident "bool"
      Empty
  Empty
  Empty
  StmtList
    Command
      Ident "echo"
      StrLit "hehe"
    Infix
      Ident "=="
      Ident "a"
      Ident "b"

Error: expression 'a == b' is of type 'bool' and has to be discarded